1. Field of the Invention
The invention relates to a solenoid valve, in particular for a brake system of a motor vehicle, having an axially displaceably supported armature, on one end of which a valve sealing body is disposed and with the other end of which a pole core is associated, and having a compression spring acting in prestressed fashion between the pole core and the armature.
Furthermore, the invention relates to an armature for a solenoid valve, in particular as it is described above, which has an axial receptacle in which a compression spring rests in at least some regions.
Finally, the invention relates to a method for producing an armature for a solenoid valve.
2. Description of the Prior Art
Solenoid valves, armatures, and methods for producing them of the generic type are known from the prior art. In particular in motor vehicle brake systems, solenoid valves are used for controlling or regulating the pressure buildup in a hydraulic system. Often, valves closed when without current are used for the purpose, which are distinguished by the fact that when the magnet actuator system is not being supplied with current, the solenoid valve is in its closed state. The magnet actuator system acts on an armature, supported axially displaceably in a housing, on one end of which a valve sealing body is disposed, which cooperates with a corresponding valve seat for closing or opening a flow opening. A pole core of the magnet actuator system is associated with the other end of the armature; when a voltage is applied, it exerts a magnetic field on the armature in order to shift it axially. So that the valve will remain closed if there is a power failure, a compression spring acting in prestressed fashion is provided between the pole core and the armature. It is known to dispose the compression spring directly between the pole core and the armature. Upon assembly, the prestressing force of the compression spring is established when the pole core is secured, for instance press-fitted, in the appropriate (axial) position in the housing. The prestressing force is greatly influenced by the various part tolerances, such as those with respect to the length of the compression spring, the installation space for the compression spring, and/or the spring rate. This can have an adverse effect on the function of the solenoid valve. Moreover, both for venting the solenoid valve and for exchanging the fluid in a reciprocating motion of the armature, longitudinal slots on the outer jacket face of the armature are provided, which reduce the cross-sectional area of the armature that influences the magnetic circuit.